Officer Nazario, along with Officer Terry Tull, responded to back up the pursuing officers.
Soon after, investigators say their cruiser was struck by the Escalade, with Butler behind the wheel, at the intersection of 39th and Wallace Streets.
After the crash, police say Butler left the scene on foot, but was apprehended at Union and Mt. Vernon Streets.
Officials say Nazario and Tull were were trapped inside their vehicle. They were rescued and taken to the Hospital of the University of Pennsylvania.
Officer Nazario was pronounced dead a short time later.
Officer Tull was admitted in critical condition, but has been upgraded to guarded condition, suffering from broken ribs and a broken hip.
Butler is now facing a number of charges including third degree murder, involuntary manslaughter and homicide by vehicle.
Police also say the Escalade Butler was driving was reported as stolen.
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